Tesla Model 3 Battery Cell Has World’s Highest Energy Density

Unfortunately, Tesla’s statement includes no hard numbers, so it’s not like we can compare the energy density of the Model 3 cells to other electric cars out there. This methodology of making a claim with no backing is quite typical in the battery cell biz and is actually a path often taken by Tesla is other areas too, including car safety claims.

So, we wouldn’t put too much faith in this statement, but here it is, regardless:

“The Model 3 battery has sophisticated power electronics, cooling systems and structure that enables high level of safety, sports-car like acceleration, Supercharging, a 120,000 mile warranty and low cost. Cells used in Model 3 are the highest energy density cells used in any electric vehicle. We have achieved this by significantly reducing cobalt content per battery pack while increasing nickel content and still maintaining superior thermal stability. The cobalt content of our Nickel-Cobalt-Aluminum cathode chemistry is already lower than next-generation cathodes that will be made by other cell producers with a Nickel-Manganese-Cobalt ratio of 8:1:1. As a result, even with its battery, the gross weight of Model 3 is on par with its gasoline-powered counterparts.”

“These batteries are steadily improving every single year – maybe around 5% improvement in their energy density their ability to store energy in a given amount of mass. That’s probably one of the key metrics we worry about. And when we went from the Roadster to the Model S, they have improved by about 40% and when we were designing the Model 3, they were about another 30% better. That improvement just continues on every single year in the background.”

I suspect the battery pack with have to be redesigned to accommodate the larger cell. There probably isn’t a reason to do that until the Model S and Model X are themselves updated. The Model S is 6 yrs old at this point. Most manufacturers would be well down the road to developing a replacement at this point.

There is no reason to do that until the cars are due for a pretty major redesign. And until the Model 3 (and maybe model Y and semi truck) ramps up so that they start to have spare capacity at the Gigafactory there is also no reason to change to limit their total output of batteries.

It does seem odd that Tesla isn’t rushing to switch out the 18650 cells for the new 2170 cells in the Model S and the Model X, given that the cost per kWh is significantly lower for the 2170 cells. My guess is that they would have moved on this already if it wasn’t for the fact that they hit a severe bottleneck at Gigafactory One in ramping up TM3 pack production.

Yeah, I know that some people are saying that a major refresh is coming soon and Tesla is waiting for that before switching to the new cells, but I don’t think that’s what they’re waiting on.

You don’t have the total number of cells in the pack, the total KWH capacity, and the total volume of the cell?

Bigger question is touched on by Benz. Why are they still using the old tech in the S & X if the new cells are sooo much better? Perhaps they are stuck to the old form factor with pack size constraints but maybe chemistry has been continuously improved to keep pace. It does seem that has been done to some degree with the changes battery capacity options they have made (60-70-75 and 85-90-100) while still keeping the same pack housing.

They’d have to reengineer the s and x while further ramping gigafactory production. That’d be dumb to do right now while they desperately need the cash from x and s to stay afloat and are already having problems ramping production.

As I recall, Tesla had a purchase agreement with Panasonic on the old form. Also, the new cell format would require a pack redesign which would require a substantial redesign of the vehicles. Until they get the Gigafactory producing at full capacity, Model 3 production is satisfying new demand (rather than pent up demand from reservations) we will probably not see the Models S/X face the major redesign that will be involved with a battery form change.

21700 cell production will be stressed as it is with upcoming Semi (2019) and Roadster plus Model Y (2020) production kicking off.

It’s possible the S/X will ultimately shift to a form skipping the 21700.

Actually, as I recall, a Tesla spokesman said there is enough “head room” in the MS/MX packs to fit the new cells in. After all, they are only 3 mm taller than the old cells. No, I don’t think that the need to redesign the pack to fit the new cells is the reason why Tesla has delayed switching over. Let’s not forget that a Tesla spokesman (I think it was Elon Musk) said before the TM3 went into production that they’d be switching the MS and MX over to the new cells before long, implying late 2017. It wasn’t until after the TM3 went into production that Tesla said it was putting off switching the existing models over to the new cells. I think the only reason that got delayed is because of the massive bottleneck in pack production at Gigafactory One using the new cells. At least, I think that’s the most likely reason for the change in plans. From what Elon said on the latest investor call, Gigafactory One still doesn’t have much excess capacity on producing Model 3 battery packs, so I don’t expect to see Tesla switching the MS and MX over to the new… Read more »

The newer 21700 are larger (21 mm diameter x 70.0 mm length) versus the classic 18650 (18 mm diameter x 65.0 mm length). And there are many manufacturers for the 18650 cell sizes, so prices are much lower. The 21700 may have more power density but even I can get 18650 cells for a few dollars each. That is what makes EVs easier to manufacturer and lower costs to the buyer. The LG Chemical cells used in the Chevy Volt, Chevy Bolt EV and other domestic brands use the larger flat cells, which reduces power density but makes manufacturing and servicing easier for a lesser cost.

Typically, cobalt is a stabilizing element in the layered crystal structure materials employed (e.g. NCM, or in the case of Tesla, NCA). With more nickel, you generally get a higher capacity, so it’s not surprising that Tesla is able to get a higher energy density. But, then, at the expense of cycle life? As a battery chemist, I fully expect the range to deplete at a faster rate. I suppose that’s the risk Tesla is willing to take- the customer sees a high range initially, but after a few years it’s noticeably worse. I guess if you’re able to get a giant range by jamming lots high-energy density cells in the car, so perhaps it won’t matter to most customers who are just commuting anyways. Interesting how customer psychology comes into play. Technically, Tesla is not lying about their claim, but they are definitely hiding this important tradeoff.

Its a smart move on Tesla’s part to reduce Cobalt even more then the new NCM 811 since Cobalt supply is getting expensive as the laggard OEMs are finally joining Tesla in moving towards large scale production of EVs.

NCA cells always had a lower cobalt content than contemporary NMC cells. As technology advances to enable NMC cells with increased nickel content, it also allows for NCA cells with even higher nickel content.

BTW, I believe I have read that the stability issues with increased nickel content are mostly a manufacturing problem, rather than cycle life?…

Mike — Go into the archives on this site and see what Tesla has been doing with Jeff Dahn in extending the life of batteries. Since they have been solving the exact same problem you are speaking of, they can trade out less cobalt.

its a 4.8ah cell, density is around 260 wh/mg. I was expecting more but tesla went the low risk route and didn’t do anything exotic with chemistry changes. The 5%/yr number is BS for wh/kg, doable for wh/L

Tesla/Panasonic glue their cells together, allowing tight packing but almost impossible to service. Look at the Weber Auto videos on YouTube and watch how Professor John Kelly (while sitting in a wheelchair) takes apart and puts together the 2017 Chevy Bolt EV battery by himself (with some electrical tools). This means it has less power density (more non-electric parts) but better servicing which is important to lower manufacturing and repair costs. Tesla servicing must be extremely costly compared to Chevy costs! Think that well before buying a Model 3 EV.

Actually, Professor Kelly states very clearly that the modules of the Bolt pack can’t be disassembled into individual cells either — so it’s not all that different from Tesla’s architecture on this score.

Frankly, I doubt anyone would actually be trying to repair these packs… Best-case scenario is likely taking out and repurposing individual modules from a broken pack.